$ git clone -n https://src.fedoraproject.org/rpms/rust-crates-io.git /var/lib/mock/f39-build-2288058-55650/root/chroot_tmpdir/scmroot/rust-crates-io
Cloning into '/var/lib/mock/f39-build-2288058-55650/root/chroot_tmpdir/scmroot/rust-crates-io'...
$ git fetch origin b95b8bcf2e5a054a27aeb7186ae604c67fdb4741:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-crates-io
 * [new ref]         b95b8bcf2e5a054a27aeb7186ae604c67fdb4741 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at b95b8bc Update to version 0.39.1; Fixes RHBZ#2256113